JP3083641B2 - System for detecting perspective distortion of a plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dividing a predetermined area where a perspective distortion of a plate-like object is to be detected into a plurality of small areas, and imaging the target by sequentially passing each of the plurality of small areas. System for detecting the perspective distortion of the plate-shaped body,
In particular, it is suitable for detecting perspective distortion of a windshield (windshield) of an automobile.

[0002]

2. Description of the Related Art Recently, an external design of an automobile has been designed to adopt a complicated three-dimensional curved surface in consideration of aerodynamic characteristics. I have. For this reason, it is difficult to keep the glass surface smooth in response to the curved surface due to the limitations of glass forming technology. Therefore, when a driver looks at an external object through the window glass, the image may appear distorted. This phenomenon is called a see-through distortion phenomenon, and when the degree of distortion increases, the driver is troublesome, which may hinder driving.

[0003] The magnitude of the perspective distortion is generally defined as a horizontal distortion angle which is a distortion angle in a horizontal direction and a vertical distortion angle which is a distortion angle in a vertical direction for each point on a plate-like body such as a window glass. It can be represented by two physical quantities. FIG.
As shown in the figure, the transverse distortion angle is an angle α formed between a horizontal line segment AB observed when there is no plate-like body and a line segment A′B ′ observed when there is a plate-like body, and The longitudinal distortion angle is defined by an angle β between a vertical line segment AC observed when there is no plate-like body and a line segment A′C ′ observed when there is a plate-like body.

[0004] The determination of the threshold distortion angle at which humans begin to see through distortion by combining the distortion angle actually detected with respect to the windshield (ie, the windshield) of the automobile and the sensory evaluation,
Makiguchi et al. Are conducting research ("Analysis of Perspective Distortion of Windshield Glass for Automobiles", 15th Multivariate Analysis Symposium of the Japan Science and Technology Corporation, November 1991). According to this, when the windshield 3 is observed from the eye point of the vehicle defined by the JIS standard, the threshold value is determined by the difference between the observation zones G1 to G4 (see FIG. 9) which are the test areas defined by the JIS standard. It was found that the distortion angles were different. When the horizontal distortion angle is plotted on the horizontal axis and the vertical distortion angle is plotted on the vertical axis, the threshold distortion angles in the observation zones G1 to G4 are approximated by a straight line (discrimination function) as shown in FIG. It is also clear that it is expressed.

FIG. 10 shows that a person perceives perspective distortion at a distortion angle corresponding to an upper side of a straight line representing a discriminant function of each observation zone of the windshield 3 and does not perceive perspective distortion at a distortion angle corresponding to a lower side. It is shown that. For example, G
For each of the observation zones 1, G2, and G3, when the lateral distortion angle is X ° and the longitudinal distortion angle is Y ° through one of the plurality of small regions constituting the observation zone, the driver can see through distortion. However, the driver does not feel the perspective distortion in the observation zone G4 even if the distortion angle is the same. Therefore, if this discriminant function is used, only by detecting the vertical and horizontal distortion angles through each of a plurality of sub-regions constituting the substantially entire region of the windshield, the perspective distortion that can be sensed by a human can be detected by the windshield. 3 can be evaluated.

[0006]

However, Makiguchi et al., When detecting the perspective distortion of the windshield 3,
As shown in FIG. 11, in a state where the windshield 3 is actually mounted on the car 9, the camera is held at the eye point (the center of the circle 10), and a straight line pattern of an orthogonal lattice is formed around the car 9. The distortion angle was detected by taking an image of the panel 17 having the image. For this reason, the following problems have occurred.

First, since it is necessary to read a very small angle of distortion from a photograph taken by a camera with human eyes, it takes a long time to read the image and the reading accuracy is very poor. Cannot be detected. In addition, since it takes a long time to attach the windshield 3 to a car, take photographs, develop, and extend the windshield 3, it is not suitable for detecting the perspective distortion of a large amount of the windshield 3, and the panel 17 has a problem. There is a problem that a large space is required due to the necessity of increasing the size.

The present invention has been made to solve these problems, and an object of the present invention is to provide a system capable of detecting a perspective distortion of a plate-like body in a short time with high accuracy.

[0009]

According to one aspect of the present invention, there is provided a system for detecting a perspective distortion of a plate-like body as described at the outset, comprising three light-emitting devices capable of emitting three light beams at a predetermined angle. A target having a target having different points, an imager for imaging the target through any one of a plurality of small areas, and a position between the imager and the target to be imaged by the imager. In order to sequentially change each of the small areas, the imaging means,
A position changing unit configured to change a relative positional relationship between the target and the plate-like body, wherein the plurality of small regions are sequentially passed through the small regions, and the target is imaged by the imaging unit. It is characterized by having done.

In this case, the plate-like body is a windshield of an automobile, and the change of the relative positional relationship by the position changing means is performed while keeping the imaging means at a point corresponding to an eye point of the automobile. Preferably.

[0011] In this case, the target 3
Preferably, the predetermined angle formed by the two light emitting points is substantially a right angle, thereby facilitating the processing of the image signal obtained from the imaging means.

In this case, the target means includes a plurality of targets each having the three light-emitting points,
In each imaging by the imaging means, it is preferable to emit light at a point where only one of the plurality of targets can emit light, thereby preventing erroneous detection and obtaining from the imaging means. Image signals can be processed with high reliability.

In this case, it is preferable that control processing means for controlling the change of the relative positional relationship by the position changing means and processing an image signal obtained from the image pickup means is provided. The transmission distortion of the plate-like body can be detected in a shorter time with higher accuracy.

Further, in this case, it is preferable that the control processing means includes means for converting the image signal into barycentric coordinates of each of the three luminous points, thereby detecting the perspective distortion of the plate-like body. Accuracy can be improved.

According to another aspect of the present invention, a system for detecting a perspective distortion of a plate-like object described at the beginning has a plurality of unit targets capable of representing a predetermined angle, and the plurality of unit targets is a predetermined angle. As for the direction, target means arranged in a sufficient number as compared with the direction intersecting with the predetermined direction, imaging means for imaging the unit target through one of the plurality of small areas, and imaging means In order to sequentially change each of the small areas located between the unit and the unit target to be imaged by the imaging unit, the imaging unit is swung substantially along the predetermined direction and the plate-shaped body is moved to the predetermined position. Position changing means that can be rotated along a direction intersecting the direction, and the unit target is photographed by sequentially passing through each of the plurality of small regions. Characterized by being configured to be able to imaging by means.

Further, in this case, the plate-like body is a windshield of an automobile, and the axis of the imaging means swings substantially through a point corresponding to an eye point of the automobile and is substantially perpendicular to the predetermined direction. It is preferable that the rotation of the plate-like body is performed about an axis substantially passing through the point and substantially parallel to the predetermined direction.

Further, in this case, it is preferable that the unit target has three light emitting points which are substantially perpendicular to each other, whereby the unit target can be accurately and reliably imaged by the imaging means. Further, the processing of the image signal obtained from the imaging means is facilitated.

In this case, in each image pickup by the image pickup means, it is preferable to emit light at a point where only one of the plurality of unit targets can emit light, thereby preventing erroneous detection . In addition, the image signal obtained from the imaging means can be processed with high reliability.

In this case, there is provided control processing means for controlling the swinging of the imaging means by the position changing means and the rotation of the plate-like body, respectively, and for processing an image signal obtained from the imaging means. It is preferable that the transmission distortion of the plate-like body can be detected in a shorter time with higher accuracy.

Further, in this case, the unit target has three light-emitting points which are substantially at right angles, and the control processing means converts the image signal into barycentric coordinates of each of the three light-emitting points. Preferably comprising means,
This makes it possible to accurately and reliably perform imaging of the unit target by the imaging unit, facilitates processing of an image signal obtained from the imaging unit, and furthermore, improves detection accuracy of the perspective distortion of the plate-like body. Can be improved.

[0021]

1 to 7 show an embodiment of a system for detecting a perspective distortion of a plate-like body according to the present invention. FIG. 1 is a schematic perspective view of the entire system. .

In FIG. 1, reference numeral 1 denotes an entire system for detecting a perspective distortion of a windshield 3 of an automobile, which is a transparent plate. The system 1 includes an LED plate 2 constituting a target unit and a C plate constituting an imaging unit.
There is provided a CD camera 4 and a mounting table 6 constituting a position changing means. The LED plate 2 includes a large number of targets having three light-emitting points each composed of an LED (light-emitting diode) 20. The CCD camera 4 is arranged so as to capture an image of the LED 20 through one of a plurality of small regions constituting a substantially entire region of the windshield 3. The small region may be a region obtained by dividing a substantially entire region of the windshield 3 into a lattice shape, and is usually divided into thousands or tens of thousands, and each small region has, for example, a substantially square shape. Good.

The mounting table 6 includes a CCD camera 4 and this CCD
Target to be imaged by camera 4 (three LEDs 2
0), the relative positions of the CCD camera 4, the target (three LEDs 20) and the windshield 3 can be changed in order to sequentially change each of the small areas of the windshield 3 located between them. Have been. For this reason, the mounting table 6 can hold the windshield 3 so as to be able to rotate in the horizontal direction, and the column 5 provided on the mounting table 6 swings the CCD camera 4 in the vertical direction. Can be supported.

In this embodiment, since the perspective distortion of the windshield of the automobile is detected, it is necessary to detect the perspective distortion when viewed from the position of the driver of the automobile, and therefore, the CCD camera is required. The vertical swing of the windshield 4 is performed about an axis (hereinafter, referred to as a “horizontal axis”) extending horizontally through a point 7 corresponding to an eye point of the vehicle, and the windshield 3 is rotated in the horizontal direction. An axis (revolution) extending in the vertical direction (that is, the vertical direction) passing through the point 7 (hereinafter, referred to as “vertical axis”)
It is performed mainly.

As shown in FIG. 1, the LED plate 2
It is arranged so that the surface on which 20 is arranged faces the CCD camera 4. The LED board 2 has a large number of LEDs 20 arranged in two rows in the horizontal direction and in the vertical direction. Specifically, as shown in FIG. 2, a total of 300 LEDs 20 are arranged in two rows in the horizontal direction and in the vertical direction. 150 rows (that is, 150 rows) are arranged in an orthogonal lattice at an appropriate length (preferably any value between 10 and 100 mm). Hereinafter, when viewed from the direction of the CCD camera 4 (that is, toward FIG. 2A), the LED 20 at the uppermost part (first row) of the left column is (1, 1), and the LED 20 at the uppermost part of the right column. Are (1, 2), the LED 20 in the n-th row in the left column is (n, 1), and the LED 20 in the n-th row in the right column is
The ED 20 represents the position of each LED 20 such as (n, 2) (where n is an integer from 1 to 150).

At the time of imaging, only the three LEDs 20 at a predetermined angle within the field of view of the CCD camera 4 are made to emit light. Specifically, (n,
1), three LEDs at positions (n, 2) and (n-1, 1), where n is an integer from 2 to 150
Only 20 emits light. Therefore, in the present embodiment, targets each composed of three light-emitting points (LEDs 20) are arranged in the horizontal direction with 149 in the vertical direction, and the light-emitting points of each target are the upper and lower targets of the target. It is common to the point that light can be emitted. The number of the targets is not necessarily one in the horizontal direction, and may be two or more. The targets may not be shared with the upper and lower targets.

The CCD camera 4 is located at the positions (n, 1), (n, 2) and (n-1, 1) through one of a plurality of sub-regions constituting a substantially entire region of the windshield 3. The three LEDs 20 are imaged. The CCD camera 4
The column 5 provided on the common base 61 of the mounting table 6 swings up and down around the horizontal axis (the swing indicated by an arrow a in FIG. 1, hereinafter, referred to as “swing a”). Is held. The column 5 has a height of the CCD camera 4 of 100 from the height of the lower side of the windshield 3.
A screw feed mechanism (for example, a screw feed mechanism using a rack and a pinion) that can be adjusted in a range of up to 500 mm (arrow h in FIG. 1) is provided so that the CCD camera 4 can be held at a point 7 corresponding to an eye point of a vehicle. It has become. The movable angle range of the swing a of the CCD camera 4 is 40 ° above the horizontal plane and 20 ° below the horizontal plane. In the present embodiment, the CCD camera 4 which is lightweight and easy to operate is used as the imaging means. However, other imaging means such as an ITV camera (industrial television camera) may be used. it can.

The windshield 3 is held by the mounting table 6 so as to rotate in the horizontal direction about a vertical axis (rotation indicated by an arrow b in FIG. 1, hereinafter referred to as "rotation b"). I have. Therefore, the CCD camera 4 swings a
When the rotation b of the windshield 3 is performed in association with the above, the LED 20 can be imaged by sequentially passing through each of the plurality of small regions constituting the substantially entire region of the windshield 3. The mounting table 6 enables the rotation b, and the windshield 3 is positioned at a position corresponding to the actual vehicle design with respect to the point 7 corresponding to the eye point.
Is configured to be held.

The mounting table 6 is provided with two rails 66 concentric with each other about the vertical axis on the upper surface of the common base 61 so that the windshield 3 rotates horizontally about the vertical axis. I have. On the rail 66, a revolving frame 62, a part of which is fitted to the column 5 and has a roller (not shown) on the lower surface, is arranged. A variable angle mechanism such as a worm gear is provided in the above part.
By the driving force from a motor (not shown) is applied to such window Omugiya, rail 6 around the axis rotating frame 62 is vertically above the roller is rolling on the rails 66
6 on. Therefore, the CCD camera 4 can always take an image of the LED 20 from the point 7 corresponding to the eye point through a plurality of small areas of the windshield 3 irrespective of the state of the rotation b of the turning frame 62. The movable angle range of the rotation b of the windshield 3 may be 70 ° on both sides of a line connecting the center of the CCD camera 4 and the center of the LED plate 2.

In order to hold the windshield 3 on the mounting table 6 at a position corresponding to the actual vehicle design with reference to the point 7 corresponding to the eye point, the mounting table 6 , A forward / backward moving frame 64 and a glass frame 65. These frames 63 to 65 are positioned between the center of the CCD camera 4 and the LE.
The left and right positions of the windshield 3 with respect to the line connecting the center of the D plate 2, the front and rear positions of the windshield 3 from the support 5 to the LED plate 2, and the windshield 3
For adjusting the mounting angle of the camera with respect to the horizontal plane. First, in order to adjust the left and right positions of the windshield 3, a left and right moving handle (not shown) provided on the turning frame 62 is rotated in a predetermined direction. Then
Revolving frame 62 and left and right moving frame 63 on it
, The left and right moving frame 63 linearly moves on a rail (not shown) provided on the revolving frame 62 (arrow c in FIG. 1). The left and right positions of the windshield 3 can be adjusted. The movable range of the left-right movement is 5 to the left and right of the line connecting the center of the CCD camera 4 and the center of the LED plate 2.
It may be in the range of 00 mm.

In order to adjust the position of the windshield 3 in the direction from the support 5 to the LED plate 2 (ie, the front-back direction), a front-rear movement handle (not shown) provided on the left-right movement frame 63 is adjusted in a predetermined direction. Rotate to.
Then, since the screw feed mechanism is provided between the left and right moving frame 63 and the front and rear moving frame 64 thereon, the front and rear moving frame 64 moves on a rail (not shown) provided on the left and right moving frame 63. Move linearly (arrow d)
Therefore, the front and rear positions of the windshield 3 can be adjusted. The movable range of the forward and backward movement is 700 to 1 as a distance in a direction from the support 5 to the LED plate 2.
It may be in the range of 600 mm.

Further, in order to adjust the mounting angle of the windshield 3 with respect to the horizontal plane, the front and rear moving frame 6
4 is rotated in a predetermined direction. Then, since an angle variable mechanism using a worm gear or the like is provided between the front-rear moving frame 64 and the glass frame 65, the glass frame 65 rotates around the axis J (arrow e). The mounting angle of the windshield 3 can be adjusted. The variable range of the mounting angle may be in the range of 20 to 90 degrees with respect to the horizontal plane. Note that the windshield 3 is attached to the glass frame 65 by a holder (not shown) provided inside the glass frame 65.

The adjustment of these three types of positions and angles is performed by manually or automatically rotating the three handles when the windshield 3 is mounted on the mounting table 6, and the detection of the perspective distortion is actually performed. When performed, these positions and angles are fixed so as not to change.

In actual distortion detection, the swing a of the CCD camera 4 and the rotation b of the windshield 3 can be manually performed. However, the system 1 according to the present embodiment
Using a motor (not shown) provided in close proximity to each of the CD camera 4 and the windshield 3, these heads a and b are rotated, and an image signal obtained from the CCD camera 4 by imaging is automatically generated. A control processing device 8 for performing the processing is provided. The control processing device 8 includes a personal computer 11 (CRT 14 capable of color display).
And a color printer 15), the image processing apparatus 1
2 and a positioning control panel 13, and further includes two motors for separately driving the windshield 3 and the CCD camera 4.

The personal computer 11 included in the control processing device 8 gives an instruction about the swing a and the rotation b to the positioning control panel 13. The positioning control panel 13 drives the two motors based on this instruction. Accordingly, the CCD camera 4 and the windshield 3 perform the predetermined swing a and the rotation b as described above. An image signal obtained from the CCD camera 4 by imaging is sent to the image processing device 12, where the barycentric coordinates of the three lit (light emitting) LEDs 20 (here, the barycenter of the light emitting LED) The coordinates are converted to a signal representing the center of the area of the LED 20 having brightness equal to or higher than a certain value on the graphic.) The signal is sent to the personal computer 11. The personal computer 11 calculates a distortion angle in a small area related to the imaging from the converted signal, and converts these data into a CRT.
14 and printed by the color printer 15. As described above, the control processing device 8 automatically and accurately controls the swing a and the rotation b of the windshield 3 and the CCD camera 4 and quickly processes an image signal obtained from the CCD camera 4 by imaging. Thus, it is possible to retrieve the detection result through the CRT 14 and / or the color printer 15 in a desired manner.

Further, as shown in FIG. 1, the system 1 of the present embodiment may include a control box 21 and an operation box 22. The control box 21 includes the LED board 2, the personal computer 11, and the operation box 2.
2 are connected. The control box 21 controls the on / off of the entire LED board 2 and determines whether the personal computer 11 or the operation box 22
Is controlled by switching a switch (not shown). When the control box 21 is switched so that each LED 20 is turned on and off by the operation box 22, the operation box 22
The arbitrary LED 20 can be turned on and off by manually operating a digital switch (not shown) provided in the device. Therefore, when the inspection of each LED 20 is required, the control box 21 is switched in this manner to switch the LE.
It is convenient to operate D20. On the other hand, each LED 20
When the control box 21 is switched so that the personal computer 11 turns on and off the light, the personal computer 11 automatically turns on and off three predetermined LEDs 20. Therefore, when actually detecting the perspective distortion, it is preferable to switch the control box 21 so that the personal computer 11 controls the LED plate 2, and in the present embodiment, the switches are switched as described above. In this state, detection of perspective distortion is performed.

FIG. 3 is a block diagram of the system 1 of the present embodiment. The personal computer 11 includes a control box 21, an image processing device 12, and a positioning control panel 13.
Is connected. Now, assuming that the control box 21 is switched so that the personal computer 11 automatically turns on and off the LEDs 20, the control box 21
About which three LEDs 20 to light from
Upon receiving the 6-bit data signal, only the specified three specified LEDs 20 are turned on. Further, the control box 21 feeds back each signal of ON, OFF and reset of each LED 20 to the personal computer 11. The positioning control panel 13 receives from the personal computer 11 a signal instructing the swing a of the CCD camera 4 and a signal instructing the rotation b of the windshield 3. The sequencer and the motor controller included in the positioning control panel 13 drive the two motors 18 and 19 according to this signal to swing the CCD camera 4 and the windshield 3 within a predetermined angle range.
And turn b. The image processing device 12 outputs an image signal obtained from the CCD camera 4 by imaging to three LEDs 2.
The signal is converted into a signal representing each barycentric coordinate of 0, and the converted signal is transmitted to the personal computer 11.
The above operation is performed by the CPU 1 of the personal computer 11.
6 (see FIG. 1) is unified.

The procedure for actually detecting the perspective distortion of the windshield of an automobile will be described below.

First, as preparation for detecting perspective distortion, LE
In order to correct mechanical errors of the D plate 2 and the mounting table 6 and obtain data serving as a reference for calculating a distortion angle, calibration measurement is performed in a state where the windshield 3 is not held on the glass frame 65 of the mounting table 6. . FIG. 4 is a flowchart of the calibration measurement. This measurement is automatically performed according to a command from the personal computer 11. In the calibration measurement, first, (150, 1), (150, 2) and (149,
The CCD camera 4 is swung a so that the three LEDs 20 at the position 1) fall within the field of view of the CCD camera 4. Then, the three LEDs 20 are turned on and CC
When the completion of the swing a of the D camera 4 is confirmed, the imaging of the three LEDs 20 is performed. The image signals obtained as a result are first sent to the image processing device 12 and converted into signals representing the coordinates of the center of gravity of the three LEDs 20, respectively. The converted signal is transmitted to the personal computer 11
And the coordinates of the center of gravity of each LED 20 are displayed on the CRT 14.

Thereafter, (150,1) and (150,1)
Both the two LEDs 20 at the position 2) are turned off, and both the LEDs 20 at the positions (148, 1) and (149, 2) are turned on. And C
The CD camera 4 is swung upward by an angle corresponding to the lattice interval, and the three lit LEDs 20 are imaged, and the coordinates of the center of gravity are displayed on the CRT 14.
These operations are repeated 149 times until the images of the three LEDs 20 at the positions (1, 1), (2, 1) and (2, 2) are taken. The data obtained as a result is written to a file as calibration data, and the calibration measurement is completed.

Next, if the windshield 3 is of a type for which the distortion angle has not yet been detected and the range in which the perspective distortion is to be detected is not clear, the control processor 8
In order to perform the automatic detection using the camera, at least one of the plurality of small areas constituting the substantially entire area of the windshield 3 held on the glass frame 65 according to the design of the vehicle is actually within the field of view of the CCD camera 4. C that fits in
It is necessary to determine the angle ranges of the swing a and the rotation b of the CD camera 4 and the windshield 3.

FIG. 5 is a flow chart for defining the detection range. In this case, the swing a of the CCD camera 4 and the rotation b of the windshield 3 are automatically performed by a command from the personal computer 11. Not done manually. For this purpose, first, as described above, the windshield 3 is positioned at the point 7 corresponding to the eye point.
The glass frame 65 of the mounting table 6 is held at a position corresponding to the actual vehicle design with reference to Next, CCD
The left end of the windshield 3 is CC when viewed from the camera 4.
The windshield 3 is manually turned b until it falls within the field of view of the D camera 4. Then, the angle of the windshield 3 at this time (hereinafter, referred to as “left limit angle”) is actually measured and input to the personal computer 11.

In this state, the CCD camera 4 is manually swung a without rotating the windshield 3 and the angle at which the small area at the top of the windshield 3 falls within the field of view of the CCD camera 4. (Hereinafter referred to as "upper limit angle")
And the small area at the bottom of the windshield 3 is CCD
Angles (hereinafter, referred to as “lower limit angles”) when they fall within the field of view of the camera 4 are actually measured, and these angles are input to the personal computer 11. Thereafter, the windshield 3 is rotated counterclockwise by an angle corresponding to the lattice spacing when viewed from above in FIG. 1, and similarly, the CCD camera 4 is manually rotated horizontally without rotating the windshield 3. The head is swung a in the direction, the upper limit angle and the lower limit angle in that state are measured, and these angles are input to the personal computer 11. The same measurement is performed until the right end portion of the windshield 3 reaches an angle that falls within the field of view of the CCD camera 4 (hereinafter, referred to as “right limit angle”). The data obtained as a result is written to a file as detection range data, and the definition of the detection range is completed.

By using the calibration data and the detection range data obtained by the above procedure, the perspective distortion of the windshield 3 can be automatically detected.

FIG. 6 is a flowchart showing the procedure for detecting the perspective distortion of the windshield. First, the calibration file and the detection range defining file are read out to the personal computer 11 with the windshield 3 held on the glass frame 65 according to the design of the vehicle as described above. Next, the windshield 3 is rotated to the left limit angle b, and the CCD camera 4 is rotated.
Is swung a to the lower limit angle at the left limit angle. (N, 1) in the field of view of the CCD camera 4;
Three L's at positions (n, 2) and (n-1,1)
The command to turn on the ED 20 is the personal computer 1
Emitted from 1, the specified three LEDs 20 are turned on.

The above-mentioned three illuminated (light emitting) LEDs 2 pass through a small area at the lower left end of the windshield 3.
The imaging of 0 is performed by the CCD camera 4. The image signal obtained as a result is first sent to the image processing device 12,
The signals are converted into signals representing the coordinates of the center of gravity of the three LEDs 20, respectively. The converted signal is sent to the personal computer 11, and the value of the distortion angle calculated by comparing the calibration data with the barycentric coordinates of the three LEDs 20 corrected by the calibration data is represented by C
Displayed on RT14.

Next, while the two LEDs 20 at the positions (n, 1) and (n, 2) are turned off, (n-
Two LEs at positions (1, 2) and (n-2, 1)
D20 is turned on. The CCD camera 4 is swung upward by an angle corresponding to the lattice interval, and passes through the small area immediately above the small area at the lower left end (n−1,
1), imaging of the three lit LEDs 20 at the positions (n-1, 2) and (n-2, 1). The same operation is repeated until the CCD camera 4 reaches the upper limit angle at the left limit angle. Thereafter, the windshield 3 is rotated b from the right to the left in FIG. 1 by an angle corresponding to the lattice interval, and the CCD camera 4 is swung a to the lower limit angle of the angle of the windshield 3. Then, (n ', 1) in the field of view of the CCD camera 4,
A command to turn on the three LEDs 20 at the positions (n ', 2) and (n'-1, 1) is issued from the personal computer 11, and the specified three LEDs 2 are turned on.
0 lights up, and the imaging is performed. The same operation is repeated until the windshield 3 rotates b to the right limit angle and the CCD camera 4 is swung a to the upper limit angle at the right limit angle. Then, the data obtained as a result is written to the file, and the detection of the perspective distortion ends.

In the system 1 of this embodiment,
The distance between the CCD camera 4 as the imaging means and the LED plate 2 as the target means is always constant for all the small areas of the windshield 3. Therefore, when the same windshield is detected, the smaller the left end area farther from the point 7 corresponding to the eye point, the more the distance between the distortion angle and the distortion angle obtained by the detection method of Makiguchi shown in FIG. Values shift. However, by correcting this error with the personal computer 11, it is also possible to evaluate the perspective distortion angle using the discriminant function obtained by Makiguchi et al.

FIG. 7 is a diagram showing a screen of the CRT 14 displaying data of the detection result of the distortion angle obtained by the above procedure. The CRT 14 is capable of color display, and can select and display any one of a vertical distortion angle, a horizontal distortion angle, and a discriminant function value calculated based on these with a function key. These values are color-coded in an appropriate range and displayed on the CRT 14 for a substantially entire area of the windshield 3. Also, if desired, a color printer 15 can print the same one displayed on the CRT 14.

As described above, in this embodiment, the time required for detecting the perspective distortion angle per windshield can be greatly reduced as compared with the conventional case.
Further, since the work of reading the distortion angle from the stretched photograph as in the case of the conventional method shown in FIG. 11 is not required, it is possible to prevent the detection of the perspective distortion angle from being low due to this work. Thus, the perspective distortion angle can be detected with high accuracy.

The present invention is not limited to the above embodiments, but can be implemented in various modes. First, CC
Of course, it is also possible to perform the detection by changing the order of the swing a of the D camera 4 and the rotation b of the windshield 3.
That is, in detecting the distortion angle of the windshield 3, first, the CCD camera 4 is fixed without swinging a.
By repeating the procedure of rotating the windshield 3 from the left limit angle to the right limit angle at this time, and then swinging the CCD camera 4 by an angle corresponding to the grid interval, the fluoroscopy of the windshield 3 is also possible. Distortion can be detected.

In this embodiment, the LED plate 2 serving as the target means has a large number of LEDs 20 arranged in a vertical direction. However, the direction in which a large number of LEDs 20 are arranged may be a horizontal direction. Then, the swing direction of the CCD camera 4 may be set to the horizontal direction, and the rotation direction of the windshield 3 may be set to the vertical direction. Further, in the present embodiment, the angle change of the swing a of the windshield 3 and the rotation b of the CCD camera 4 are performed intermittently at an angle corresponding to the lattice interval. Although the change is performed, the angle change of the swing a and the rotation b may be performed continuously, and the imaging may be performed at regular time intervals.

[0053] In the present embodiment has been windshield 3 and a CCD camera 4 so as to swing a and pivoting b in different directions, the invention according to claim 1 to 6 are to The three LEDs 2 forming a predetermined angle by sequentially passing through each of the plurality of small areas constituting the predetermined area of the windshield 3 are not limited.
0, the windshield 3 and the L
The relative position of the ED plate 2 may be changed by another method. As a specific example, only the windshield 3 is rotatably held in both the vertical direction and the horizontal direction around the point 7 corresponding to the eye point, and has only three LEDs 20 forming a predetermined angle. LED board 2 and CC
It is conceivable to arrange the D camera 4 fixedly. As still another example, the CCD camera 4 is swingably held in both the vertical and horizontal directions around the point 7 corresponding to the eye point, and the windshield 3 is fixedly arranged, and at a predetermined angle. Only three LEs
It is conceivable to move the LED plate 2 having D20 in the vertical and horizontal directions according to the swing of the CCD camera 4.

In this embodiment, the CCD camera 4
The swing a of the windshield 3 and the rotation b of the windshield 3 are performed in the same manner as described above.
The LED plate 2 may be moved up and down in accordance with
In this case, the LED plate 2 may have only three LEDs 20 forming a predetermined angle.

In this embodiment, the luminous body (LED 20) is used as the target from the viewpoint of preventing erroneous detection. However, in the inventions according to claims 7 to 12 , the luminous body (LED 20) is not particularly used. May be any mark that can be imaged by the CCD camera 4, and for example, may be a linear pattern arranged in a grid pattern.

Further, the present invention can detect not only the perspective distortion of the windshield of an automobile but also the perspective distortion of any transparent plate-like body. .

[0057]

According to the present invention, as in the case of the conventional method shown in FIG. 11, it is necessary to attach a plate-like body such as a windshield to an automobile or the like in a practically used mode and to take a photograph. In addition, since the perspective distortion of the plate-like body can be detected in a short time and with high accuracy, the plate-like body that causes the perspective distortion can be eliminated in advance before actual mounting.

According to the first to sixth aspects of the present invention, since the target only needs to have three light emitting points at a predetermined angle, the target can be simply constituted by a light emitting element such as an LED. In addition, the imaging of the target by the imaging means can be performed accurately and reliably.

Further, according to the inventions described in claims 7 to 12, it is not necessary to wrap a panel having an orthogonal lattice linear pattern around an automobile as in the case of the conventional method shown in FIG. No large space is required to detect the perspective distortion of the plate-like body.

According to the third and ninth aspects of the present invention, since the target has three light-emitting points that are substantially perpendicular to each other, it is easy to process an image signal obtained from the imaging means.

According to the fourth and tenth aspects of the present invention, in each image pickup by the image pickup means, a point where only one of the plurality of targets can emit light is caused to emit light. And can prevent
An image signal obtained from the imaging means can be processed with high reliability.

Further, according to the fifth and eleventh aspects of the present invention, the control processing for controlling the change of the relative positional relationship between the imaging means, the target and the plate-like body and processing the image signal obtained from the imaging means. Because the device is equipped,
The perspective distortion of the plate-like body can be detected in a shorter time with higher accuracy.

Further, according to the present invention, the control processing means converts the image signal obtained from the image pickup means into the barycentric coordinates of each of the three light-emitting points constituting the target. , The detection accuracy of the perspective distortion of the plate-like body can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an entire system in one embodiment of a system for detecting perspective distortion of a plate-like body according to the present invention.

FIG. 2A is a front view of the LED plate shown in FIG. 1 with a middle part cut away, and FIG. 2B is a partially enlarged view thereof.

FIG. 3 is a block diagram of the system shown in FIG. 1;

FIG. 4 is a flowchart of calibration detection performed in the system shown in FIG. 1;

FIG. 5 is a flowchart of a detection range definition performed in the system shown in FIG. 1;

FIG. 6 is a flowchart of detection of perspective distortion of a windshield performed in the system shown in FIG. 1;

FIG. 7 is a view showing a screen of a CRT displaying a detection result of perspective distortion obtained by the steps shown in FIGS. 4 to 6;

FIG. 8 is a diagram for explaining a definition of a perspective distortion angle of a plate-like body.

FIG. 9 is a diagram illustrating distinction of observation zones of a windshield when observed from an eye point of an automobile.

FIG. 10 is a graph showing a discriminant function for each observation zone shown in FIG. 9;

FIG. 11 is a diagram showing a conventional method for detecting perspective distortion of a windshield.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 System 2 LED board (target means) 3 Windshield (plate-like body) 4 CCD camera (imaging means) 5 Support 6 Mounting table (position changing means) 7 Point corresponding to eye point 8 Control processing unit 20 LED (light emission possible) 21) Control box 22 Operation box 61 Common base 62 Swivel frame 63 Left / right moving frame 64 Front / back moving frame 65 Glass frame 66 Rail

Continuation of the front page (56) References JP-A-3-199946 (JP, A) JP-A-3-135704 (JP, A) JP-A-2-96641 (JP, A) (58) Fields studied (Int) .Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01N 21/84-21/958

Claims (12)

(57) [Claims] 1. A perspective view of a plate-like body in which a predetermined area where a perspective distortion of the plate-like body is to be detected is divided into a plurality of small areas, and a target is imaged through each of the plurality of small areas sequentially. A distortion detecting system, comprising: a target unit having a target having three light-emitting points at a predetermined angle; an imaging unit configured to image the target through one of the plurality of small regions; A position at which the relative positional relationship between the imaging means, the target, and the plate-like body can be changed in order to sequentially change the small areas located between the means and the target to be imaged by the imaging means. Changing means, wherein the plurality of small areas are sequentially passed through each of the small areas so that the target can be imaged by the imaging means. Stem. 2. The vehicle according to claim 1, wherein said plate-like body is a windshield of an automobile, and said relative positional relationship is changed by said position changing means while maintaining said imaging means at a point corresponding to an eye point of said automobile. The system of claim 1, wherein the system comprises: 3. The system according to claim 1, wherein the predetermined angle formed by the three light-emitting points of the target is substantially a right angle. 4. The target means comprises a plurality of targets having the three light emitting points, and in each image pickup by the image pickup means, a point at which only one of the plurality of targets can emit light. The system according to claim 1, wherein the system emits light. 5. The apparatus according to claim 1, further comprising control processing means for controlling a change of said relative positional relationship by said position changing means and processing an image signal obtained from said imaging means. System. 6. The control processing means according to claim 3, wherein
6. The system according to claim 5, including means for converting each of the light-emitted points into barycentric coordinates. 7. A perspective view of a plate-like body in which a predetermined area where a perspective distortion of a plate-like body is to be detected is divided into a plurality of small areas, and a target is imaged through each of the plurality of small areas sequentially. In a distortion detecting system, a target means having a plurality of unit targets capable of representing a predetermined angle and having a sufficient number of unit targets arranged in a predetermined direction as compared with a direction intersecting the predetermined direction. An imaging unit for imaging the unit target through any one of the plurality of small regions; and each of the small regions located between the imaging unit and the unit target to be imaged by the imaging unit. In order to change, the imaging means can be swung substantially along the predetermined direction and the plate-like body can be rotated along a direction intersecting the predetermined direction. And a position changing means, the system characterized by being configured so as to be captured by the plurality of small areas for each small area sequentially the imaging unit the unit target through. 8. The vehicle according to claim 1, wherein the plate-like body is a windshield of an automobile, and a swing of the imaging means substantially passes through a point corresponding to an eye point of the automobile and is centered on an axis substantially perpendicular to the predetermined direction. 8. The system according to claim 7, wherein the rotation of the plate is performed about an axis substantially passing through the point and substantially parallel to the predetermined direction. 9. The system according to claim 7, wherein the unit target has three light-emitting points that are substantially perpendicular to each other. 10. The apparatus according to claim 7, wherein, in each image pickup by said image pickup means, a point where only one of the plurality of unit targets can emit light is emitted. The described system. 11. A control process hand for processing the image signals obtained from the respective controlling and said imaging means swinging and rotation of the plate-like body of the imaging unit by the position changing means
The system according to any of claims 7 to 10, comprising a step . 12. The unit target according to claim 3, wherein said unit targets form a substantially right angle.
12. The image processing apparatus according to claim 11, further comprising: a plurality of light-emitting points, wherein the control processing means includes means for converting the image signal into barycentric coordinates of each of the three light-emitting points.
System.